This invention relates to a chain tensioner for chain drives in general which is particularly though not exclusively suitable to use as a tensioner on the timing chain of a motor vehicle engine.
The present invention is based on the utilization of a synthetic plastic material that will "creep" under load and elevated temperature. One form of chain tensioner embodying this principal is disclosed in our British Patent No. 986,174 but this form of construction is only of limited application for use in confined spaces. Another example of this type of chain tensioner is shown in our U.S. Pat. No. 3,490,302. It is an aim of this invention to provide a simple, compact, reliable, and easy to manufacture chain tensioner.
However, these prior art chain tensioners have manufacturing and installation limitations that make the parts more expensive to manufacture and assemble. In one such prior art chain tensioner the blade spring has a triangular aperture at one end that must be aligned with a triangular projection on the shoe. When the triangular projection is entered into the triangular aperture a split pin is inserted into a bore in the projection to mechanically interlock the blade spring on the shoe. A small misalignment of the components can prevent the tensioner from being properly assembled. Accordingly, there is a need for a simplified chain tensioner that is easy to manufacture and assemble.